Electric plug



Sept 9, 1941- E. P. sEGHERs A 2,255,336

ELECTR I C PLUG Y Filed Ooi. 19, 1939 Patented Sept. 9, 1941 UNITEDSTATES PATENT QFFCE.

ELECTRC PLUG Emiel P. Seghers, Chicago, Ill. Application October 19,1939, Serial No. 300,125

2 Claims.

This invention relates to decorative lighting equipment moreparticularly to a plug for connecting such equipment to a source ofcommercial current and has for its principal object the provision of anew and improved devi-ce of this kind.

Decorative lights such as are commonly used for decorating Christmastrees usually comprise a plurality of individual lamps connectedtogether in series and the series combination connected to a source ofelectric current. In decorating the tree the string of lamps so formedis trained over the branches oi the tree and thest'ring is then pluggedinto a suitable source of current. In order to facilitate placing thelamps upon the tree the plug by which the string is connected to thesource of current is arranged so that either one or both ends of thestring may be readily separated from the plug. Y

It is the further object of the invention toprovide a plug in which oneor both ends of a string of lights are connected by removableconnections.

Stillanother object of the invention resides in the provision of a plugof this type kin which the electrical parts are at all times fullyinsulated to guard against shock.

Still another object of the invention resides in the provision of aterminal for use on the string of lights and adapted to establishing aconnection with the plug, the terminal being insulated so that a personwill not receive a shock from the plug in the normal use of it.

Further objects of the invention, not specically mentioned here, Will beapparent from the detail description and claims which follow, referencebeing had to the accompanying drawing in f which preferred embodiment ofthe invention is shown by Way of example and in which:

Figure 1 is a diagrammatic'al illustration of the principle of theinvention;

Figure 2 is a cross-sectional elevational view through a plug andcooperating terminal taken substantially along the line 2 2 of Figure 3looking in the direction of the arrows;

Figure 3 is a bottom side plan view of the plug shown in' Figure 2 withthe bottom plate removed;

Figure 4 is a view similar to Figure 2 showing a modified form of theinvention;

Figure 5 is a bottom side plan View of the plug shown in Figure 4 withbottom plate removed;

Figure 6 is a bottom side plan view of still another embodiment of theinvention. with the bottom plate removed; v

Figure '7 is a View similar to Figure 2 taken along the line l-l ofFigure 6;

Figure 8 is a cross-sectional vievv taken along the line 8-6 of Figure 6looking in the direction of the arrow; and

Figure 9 is a perspective view of the current carrying element of theplug shown in Figures 6 to 8 inclusive.

In my co-pending application, Serial Numberv 129,130, led March 5, 1937,which issued as Patent No. 2,180,121 on Nov. 14 1939, of whichapplication the instant application is a continuation in part, there isshown an improved decorative light device suitable for use on Christmastrees and the like, One `of the features ci the invention shown in thisco-pending application is an arrangement for attaching one end of astring of Christmas tree lights to a plug in such a manner that the Yconnection may be broken during the process of placing the lamps upon aChristmas tree or other object that is being decorated. As will beappreciated by those skilled inthe art, when this connection is brokenand the plug and one side of the string of Christmas tree lights isconnected to a source of electric current, the full voltage of thatsource of current will be on the removable terminal. Should a person inplacing the string upon the object being decorated come in contact withthat terminal he Will receive a shock Which, under certaincircumstances, might be fatal. Furthermore, if the terminal comes incontact with a grounded device such as a radiator an arc is likely to bestruck and it is possible that a re'might ensue.

'Ihe instant invention includes an arrangement of plug and removableterminal therefor in which the current carrying elements are protectedby insulation in such a manner that it is impossible for a person tocome in contact with them or for the element to come in contact with agrounded object during the time that the device is being put into place.When the terminal is inserted into the plug to complete the connectionthe insulating device extends into the insulating shell of the plug sothat the connection is properly insulated and the circuit Will not beshort circuited should a metallic decorative member fall upon it.

Referring novv tothe drawing more in detail, particularly to Figure 1,Where there is diagram matically illustrated a string of decorativelights l connected together With Wires 2, the end wires being connectedto a plug 3 by which connection is made to a source of electric current.The plug 3 has the usual prongs 4 projecting from a casing 5 that iscomposed of an insulating material. One of the connecting Wires 2extends into the casing 5 and is connected to one of the prongsll andthe connecting Wire at the other end of the string terminates in aterminal 'I that is detachably connected to the other prong 4 within thecasing 5.

As Will be seen in Figures 2 and 3, the plug casing 8 is a cup likecasing containing internal bosses 9 upon which are fixed terminalmembers II) and II, terminal member I including a prong I2 whichprojects from the casing. rI'erminal member II contains a similar prongI3. Usually a casing of this kind is composed of a molded insulatingmaterial such as Bakelite and the cavity portion of the casing is closedby a bottom plate I4 which is composed of fiber or Bakelite and isperforated to permit the prongs I2 and I3 to extend through it.

Casing 8 contains a perforation I5 located upon the median line of theplug and with which a terminal member I6 is aligned. Terminal member I6is connected to and carried by the member I, and contains a slot openinginto its free end so as to provide contact tension as will be wellunderstood by one skilled in the art.

The casing also contains a perforation through which the wire 2 of astring of lamps is extended and connected to the terminal I I, thisconnection being made by a screw in the usual manner, or if desired thescrew may be omitted and the wire soldered directly to the terminal.

The wire 6 terminating the other end of the string of lights extendsinto an insulating shell I preferably generally cylindrical in shape andwithin which female terminal member I'I is located, the wire beingattached to this member; preferably by soldering. 'Ihe shell 'I isadapted to t in the perforation I5 so that the terminal I'I may beprojected into the casing 8 and into electrical connection with themember I6 thereby to complete the circuit of the string of lamps. Femaleterminal I 'I is slotted so that when engaged vwith terminal I6 a goodelectrical contact will be made. It will be noted that the member I'I isset well back from the open end of the shell 1 so that it is protectedand a person manipulating the casing is not likely to come in contactwith the terminal. It will also be noted that the diameter ofperforation I5 is small and that member I6 terminates well within casing3 so that there is little danger of a person receiving a shock in thenormal operation of the device.

In the embodiment of the invention shown in Figures 4 and 5 a similarmolded outer casing I3 is provided with a single cross bridge I9 uponwhich prong members 2l] and 2I are xed. Projected through this bridge I9is a female terminal member 22 which is connected to the prong 20 in anypreferred manner such as by a wire or strap 23. Member 22 is providedwith a slot opening into its free end to provide resiliency in themember. The end wire 2 of the string of lamps is brought into the casingand connected to the prong member 2I. The wire 6 on thel other end ofthe string projects into a shell 24 and is terminated upon a maleterminal member 25 disposed wholly within the shell. Casing I8 isperforated at 26 to receive the shell 24 so as to permit the terminal 25to be brought into contact With the female terminal 22 in the plugcasing.

As will be understood by those skilled in the art, plugs of the typeshown in Figures 2 to 5 inclusive are frequently provided with suitableperforations in the face of the plug opposite the prongs so as to permitthe prongs of another plug to be inserted into the casing and to makecontact with terminal members, such as I0 and II', Figure 3. Such anarrangement permits building up a cluster of plugs and thereby enables aplurality of string of lamps to be lighted from one electric outlet, andthe use of plugs of this type is contemplated.

In the embodiment of the invention shown in Figures 2 to 5 inclusive oneside of the string of lights is permanently connected to the plug andthe other side is connected through the removable terminal. In theembodiment shown in Figures 6 to 9 inclusive the string of lights mayterminate on both ends in suitable terminals both of which are adaptedto be detachably connected to the plug, or if desired, two strings maybe connected to a single plug. In this embodiment the casing 30 isprovided with two generally rectangular bridges 3| which form socketsinto which the foot portion 32 of a terminal member is nested. Thisterminal member consists of a prong 33 for spring terminal 34 and aterminal 35. Each plug contains two of these elements. As will be seenbest in Figure 8, the outer casing 30 contains a central post 36 whichis generally rectangular in shape and against which a portion of thespring terminal 34 is located. The casing contains perforations 31through which the prongs of another plug are inserted and brought intocontact with the spring terminals 34.

'I'he post terminals 35 are mounted upon a base 38 which is disposedalongside of a face of the central post 36, .the terminals 35 being thusaligned with perforations 39 in the side walls of the outer casing 30.The assembly of parts is held in the casing by a plate 40 that isattached to the central post 36 by a screw 4I and is perforated topermit the prongs 33 to extend out of the casing and to be brought intocontact with a source of electric current.

The end wire of string of Christmas tree lamps such as for instance thewire 6, Figure 7, extends into a generally cylindrical shell 42 and isconnected to a terminal member 43 that is disposed therein. The terminal43 falls short of the end of the casing 42 to prevent the terminal frombeing engaged during manipulation of the device. Shells 42 are of suchdiameter that they may be extended into the casing 30 throughperforation 39 to bring the terminal 43 into engagement with one of theterminals 35.

As shown in Figures 6 to 9 inclusive terminal 35 is a male terminal andterminal 43 is a female terminal. If desired the position of theseterminals may be reversed in the manner shown in Figures 2 to 5inclusive, that is, the female terminal may be carried on base 38 andthe male terminal may be placed in shell 42. Preferably both ends of thestring of lamps is provided with a terminal and shell such as 43 and 42and are connected to one plug as shown. If desired, however, a singleplug may be made to serve two strings in which case one end of onestring will be permanently connected to one prong 33 in the manner fullyillustrated in Figures 2 to 5 and the one end of the other string willbe permanently connected to the other prong 33. The terminal ends of thetwo strings will be connected to the terminals 35 and, if desired,suitable marks may be employed to indicate to which side the terminalmust be connected.

From the foregoing it will be seen that the devices of my invention arepossessed of many advantages. They are inexpensive to construct andmaintain; they are fully insulated so that a person cannot readily beshocked in manipulating the device; they are convenient and will makethe problem of Stringing a string of lamps upon a Christmas tree muchmore simple.

While I have chosen to illustrate my invention by showing and describinga preferred embodiment of it, I have done so by Way of example. As thereare many modications and adaptations which can be made by one skilled inthe art Within the teachings of the invention.

Having thus complied with the statutes and shown and described apreferred embodiment of my invention of What I consider new and desireto have protected by Letters Patent is pointed out in the appendedclaims.

What is claimed is:

1. In an electric plug, a pair of current carry- `ing members eachcomprising, an L shaped rigid member the longer leg of which forms aprong, a flexible member iixed to the shorter leg of said irst memberand extending therefrom in substantial parallelism to said prong, aContact integral with said flexible member and extending from the endthereof back at an angle toward said shorter leg, a base integral withsaid flexible member and disposed at right angles thereto and to saidprong, a male terminal projecting from said base, a casing composed ofinsulating material andhaving internal cavities for receiving saidcurrent carrying members and holding the same with said prongs and basesdisposed in substantially parallel planes, said casing havingperforations through which other plug prongs may extend to engage saidcontacts and having other perforations through which female terminalmembers may extend and engage said male terminals, and means including adisk having perforations through which said prongs extend for holdingsaid current carrying members in said casing.

2. The combination in an electric plug of a cup-shaped shell composed ofinsulating material, a rectangular post centered Within said shell andextending from the closed end thereof, a pair of bridges disposed Withinsaid shell and spaced from said post, a pair of L-shaped male contactorseach having a foot portion resting on one of said bridges and a longercontact portion extending out of said shell, a spring terminal :for eachof said contactors comprising, an L-shaped base engaging two sides ofsaid post, an arm extending from one end of one section of said base andfixed to the foot portion of the male contactor, a terminal armextending from the other end of said base section and toward said arm,and male contact means projecting from the other section of said base,there being perforations in said shell through which said springterminals are accessible to other plugs, a disk iitted in the open endof said shell to close the same, and bearing against the foot portionsof said contactors, there being perforations in said disk through whichsaid male contactors extend, and means engaging said disk and post forholding the assembly ,together Within said shell.

EMIEL P. SEGHERS.

